One of my friends at university was a chemistry student. Instead of writing essays or sitting exams he was judged on the experiments he conducted in his laboratory. He’d combine chemicals together to see how they reacted. Some would crackle, some would pop, and some would produce a catastrophic nuclear meltdown so he largely avoided those experiments.

In general, he wouldn’t add chemicals together randomly. Everything was meant to be based on analysis on paper before moving to the actual chemicals themselves. But he was a student – and students always take shortcuts. So, sometimes he would add the chemicals together before he worked out everything that might happen to them.

One day he came home and he couldn’t talk. When I said “hello” he took out a notepad and wrote “hello” on it. “What happened,” I asked. He wrote “I invented mustard gas!”. 

Later, when his voice returned, he explained what happened. 

“I was trying to combine a couple of chemicals together to create a detergent like gas. It was meant to be a mild cleanser that you could use as a spray to keep your hands clean. Unfortunately, I got my measurements wrong. Even worse, I forgot the danger of sniffing the gas. When you sniff a gas in a test tube you should use your hand to gently waft the air towards you. And then you should only do that if it is completely safe. I, however, accidentally created mustard gas. And then I sniffed the test tube like Scarface with nasal deep in a mountain of cocaine. The gas burned my throat and I had to drink cups of butter for a week to keep it moist and to stop it scarring over.”

However, even after accidentally giving his throat an acid bath and downing liquid Lurpack unsalted like it was a pint of lager, if you asked him what the worst smell in the world was, then his homemade mustard gas would only be number 2 on his list. At number 1 he would say “your smelly trainers!”

It seems unfair that your own boady can generate a smell that your own nose rejects. Why is it that one whiff of a pair of trainers after a long run can know you out faster than Anthony Joshua against, well, anyone? 

When I travel with my trainers, I have to make sure to wrap them not just in a trainer back but two bin bags too. I can’t risk the cross contamination of having my trainers in the same bag as my clothes. Instead, I wrap them so tightly I’ve created a vacuum so powerful James Dyson wants to patent it.

But, no more. 

Last month my wife bought me a special gift: charcoal bags from Shoe Ninja. Special bags that fit inside each trainer and draw out the moisture (and the smell). How they work, I don’t know. Do they work? I don’t know either. I think they do. I think that when I take the bag out of the shoe, the shoe doesn’t smell as strong as it would have if there had been nothing there. But I can’t tell for certain. 

The one thing that makes me think they might have no practical benefit is that the instructions ask me to ‘refresh’ the shoe ninja each month by leaving them out in the sunshine so the sunshine can ‘recharge’ the charcoal. Which doesn’t sound like any science I know, especially when the charcoal is in a cloth bag and has as much chance of seeing the sun as, well, Tony Montana seeing the next day at the end of Scarface. It sounds as daft as snorting mustard gas.

So, can I recommend this product? Maybe. It might work but then again it might not!